What is OSI Model? Seven layer of the OSI model?

Hello..guyzz..! welcome back my blogger my name is Dinesh Kumar Gupta.
    Friends...today I will discuss What is OSI Model? and Describe 7 effective Layer of the OSI Model as well as understand PDU (Protocol Data Unit) of the OSI Model.

 So let's start now, first of all 

What is OSI Model?

OSI Stands for Open System Interconnection. It was published in 1984.
OSI model was first proposed by International Standard Organization (ISO) to solve the multiple problems faced in Telecommunication it is a conceptual model of telecommunication networking where the whole process is divided into seven effective layers. 

SEVEN LAYER OF THE OSI MODEL

(1) Application Layer
(2) Presentation Layer
(3) Session Layer
(4) Transport Layer
(5) Network Layer
(6) Data-Link Layer
(7) Physical Layer 

And According to formate of the OSI Model

(1) Physical Layer
(2) Data-Link Layer
(3) Network Layer
(4) Transport Layer
(5) Session Layer
(6) Presentation Layer
(7) Application Layer

Let's understand every layer of the OSI Model

 (1) Physical Layer:- This layer is the primary layer of the OSI Model and consists of connecting device such as Ethernet cable, Token ring, hubs,                                            repeaters. this layer responsible for connecting the device to physical transmission media such as copper or optical or  Radiofrequency and also called the hardware layer or lower layer.

                                  

(2) Data-Link Layer:- in this layer encode and decode data packet into bits and using its transmission protocol. it handles the error in the physical layer. it also controls flow and synchronization of the frame and at the same time, it manages controlling access to the physical layer network device.

(3) Network Layer:- In this layer adds the concept of routing above the data link layer. When data arrives at the network layer, the source and destination address contained inside each frame are examined to determine if the data has reached its final destination. if the data has reached the final destination, this layer 3 formats the data into packet delivered up to the Transport layer.

(4) Transport Layer:- In the fourth layer, the variable length data sequence has to be transferred from source to destination host through one to more network. this Transport layer delivers data across the network connection.The supported protocol at this layer are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol)

(5) Sessions Layer:- In this layer responsible communication or connection between the computer and establishing connections between local and remote applications.

(6) Presentation Layer:- In this layer here is a simple function of any pieces of the OSI model. here is handled syntax processing of the message data such as formate of data, encryption/decryption. 

(7) Application Layer:- In the last layer of the OSI model this layer represents the data is understood by the end user.the application layer supplies network services to the end-user application. network services are typically a protocol that works with user's data.
for example, in a web browser application, the application layer protocol "HTTP" (Hyper Text Transfer Protocol ) is also called a software layer or upper layer.

PDU in OSI Model:-

(1) Application Layer:- DATA ( the data received or transmitted by a software                                                                  application )
(2) Presentation Layer: -DATA ( Formatted of data )
(3) Session Layer:- DATA  ( The data passed to the network connection )
(4) Transport Layer:- SEGMENT (A segment that includes a TCP header and                                                                      data)
(5) Network Layer:- PACKET  ( contain the source and destination address)
(6) Data-Link Layer:- FRAME ( Series of bits )
(7) Physical Layer:- BITS  ( 0, 1 )